6cbbc36ea1
1. Support where clause in export stmt which only export selected rows.
The syntax is following:
Export table [table name]
where [expr]
To xxx
xxxx
It will filter table rows.
Only rows that meet the where condition can be exported.
2. Support utf8 separator
3. Support export to local
The syntax is following:
Export table [table name]
To (file:///xxx/xx/xx)
If user export rows to local, the broker properties is not requried.
User only need to create a local folder to store data, and fill in the path of the folder starting with file://
Change-Id: Ib7e7ece5accb3e359a67310b0bf006d42cd3f6f5
4.4 KiB
4.4 KiB
title, language
| title | language |
|---|---|
| EXPORT | en |
EXPORT
Description
This statement is used to export data from a specified table to a specified location.
This function is implemented by broker process. For different purpose storage systems, different brokers need to be deployed. Deployed brokers can be viewed through SHOW BROKER.
This is an asynchronous operation, which returns if the task is submitted successfully. After execution, you can use the SHOW EXPORT command to view progress.
Grammar:
EXPORT TABLE table_name
[PARTITION (p1 [,p2]]
[WHERE [expr]]
TO export_path
[opt_properties]
[broker];
1. table_name
The table names to be exported currently support the export of tables with engine as OLAP and mysql.
2. partition
You can export only certain specified partitions of the specified table
3. expr
Export rows that meet the where condition, optional. If you leave it blank, all rows are exported by default.
4. export_path
The exported path needs to be a directory. At present, it can't be exported to local, so it needs to be exported to broker.
5. opt_properties
Used to specify some special parameters.
Grammar:
[PROPERTIES ("key"="value", ...)]
The following parameters can be specified:
column_separator: Specifies the exported column separator, defaulting to t. Supports invisible characters, such as'\x07'.
line_delimiter: Specifies the exported line separator, defaulting to\n. Supports invisible characters, such as'\x07'.
exec_mem_limit: Exports the upper limit of memory usage for a single BE node, defaulting to 2GB in bytes.
timeout: The time-out for importing jobs is 1 day by default, in seconds.
tablet_num_per_task: The maximum number of tablets that each subtask can allocate.
6. broker
Broker used to specify export usage
Grammar:
WITH BROKER broker_name ("key"="value"[,...])
Here you need to specify the specific broker name and the required broker attributes
For brokers corresponding to different storage systems, the input parameters are different. Specific parameters can be referred to: `help broker load', broker required properties.
When exporting to local, you do not need to fill in this part.
example
1. Export all data from the testTbl table to HDFS
EXPORT TABLE testTbl TO "hdfs://hdfs_host:port/a/b/c" WITH BROKER "broker_name" ("username"="xxx", "password"="yyy");
2. Export partitions P1 and P2 from the testTbl table to HDFS
EXPORT TABLE testTbl PARTITION (p1,p2) TO "hdfs://hdfs_host:port/a/b/c" WITH BROKER "broker_name" ("username"="xxx", "password"="yyy");
3. Export all data in the testTbl table to hdfs, using "," as column separator
EXPORT TABLE testTbl TO "hdfs://hdfs_host:port/a/b/c" PROPERTIES ("column_separator"=",") WITH BROKER "broker_name" ("username"="xxx", "password"="yyy");
4. Export the row meet condition k1 = 1 in the testTbl table to hdfs.
EXPORT TABLE testTbl TO "hdfs://hdfs_host:port/a/b/c" WHERE k1=1 WITH BROKER "broker_name" ("username"="xxx", "password"="yyy");
5. Export all data in the testTbl table to the local.
EXPORT TABLE testTbl TO "file:///home/data/a";
6. Export all data in the testTbl table to hdfs, using the invisible character "\x07" as the column and row separator.
EXPORT TABLE testTbl TO "hdfs://hdfs_host:port/a/b/c" PROPERTIES ("column_separator"="\\x07", "line_delimiter" = "\\x07") WITH BROKER "broker_name" ("username"="xxx", "password"="yyy")
keyword
EXPORT